It is announced on gundam_unicorn twitter that on March 5th (the premiere date of Gundam UC episode 3 'Spectre of Laplace' in movie theatres @ Japan) a special edition Gundam UC Ace Vol.2 will be on sale in Japan to include the limted MG Unicorn Beam Gatling Gun kit.

This gives us hope that the MG Sinanju Rocket Bazooka might be a potential come back item for sale later too.